fix the system_id key in llvm and add a shameful hack to pass travis

src/python/pants/backend/native/subsystems/binaries/llvm.py

@@ -24,7 +24,7 @@ class LLVMReleaseUrlGenerator(BinaryToolUrlGenerator):
   # TODO(cosmicexplorer): Give a more useful error message than KeyError if the host platform was
   # not recognized (and make it easy for other BinaryTool subclasses to do this as well).
   _SYSTEM_ID = {
-    'darwin': 'apple-darwin',
+    'mac': 'apple-darwin',
     'linux': 'linux-gnu-ubuntu-16.04',
   }
 

src/python/pants/backend/python/tasks/setup_py.py

@@ -166,12 +166,14 @@ def as_environment(self):
         native_tools.cpp_compiler.path_entries +
         native_tools.linker.path_entries
       )
-      ret['PATH'] = get_joined_path(all_path_entries)
-
       # FIXME(#5662): It seems that crti.o is provided by glibc, which we don't provide yet, so this
-      # lets Travis pass for now (and doesn't harm anything if it doesn't exist / is probably the
-      # right thing if it does).
-      ret['LD_LIBRARY_PATH'] = '/usr/lib/x86_64-linux-gnu'
+      # lets Travis pass for now.
+      ret['PATH'] = native_tools.linker.platform.resolve_platform_specific({
+        'darwin': lambda: get_joined_path(all_path_entries),
+        # Append our tools after the ones already on the PATH -- this is shameful and should be
+        # removed when glibc is introduced.
+        'linux': lambda: get_joined_path(all_path_entries, os.environ.copy()),
+      })
 
     return ret
 

tests/python/pants_test/backend/python/tasks/test_python_distribution_integration.py

@@ -142,8 +142,8 @@ def test_pants_resolves_local_dists_for_current_platform_only(self):
 
   def test_pants_tests_local_dists_for_current_platform_only(self):
     platform_string = Platform.create().resolve_platform_specific({
-      'linux': lambda: 'linux-x86_64',
       'darwin': lambda: 'macosx-10.12-x86_64',
+      'linux': lambda: 'linux-x86_64',
     })
     # Use a platform-specific string for testing because the test goal
     # requires the coverage package and the pex resolver raises an Untranslatable error when